Rotary displacement pump

ABSTRACT

A rotary displacement pump of novel construction is disclosed, the pump having a multiportion housing with a sleeve of elastic material disposed within the interior of the housing. The sleeve has sealing strips at the edges thereof as well as a crosspiece disposed between the suction and the delivery sides of the pump, the sleeve furthermore being rigidly mounted against rotation and connected with the housing. A rotor is disposed in the interior of the sleeve for deflecting the sleeve outwardly in at least two locations, the rotor effecting the outward deflection of the sleeve as the rotor rotates against the inside wall of the housing to thereby produce a plurality of sealing contacts which divide the space between the housing and the sleeve into traveling pockets. The sealing strips provided at the edges of the sleeve are clamped into portions of the housing and furthermore are acted upon, via a connecting channel, with a pressure medium so as to avoid sealing losses even at high pump speeds and high delivery quantities.

United States Patent [72] Inventor Siegfried Stauber lluttenkoplstrasse 32, Zurich, Switzerland [2]] Appl. No. 846,740 [22] Filed Aug. 1, 1969 [45] Patented June 8, 1971 [32] Priority Aug. 9, 1968 [33] Switzerland [31] 11992/68 [54] ROTARY DISPLACEMENT PUMP 8 Claims, 5 Drawing Figs.

[52] US. Cl 418/45, 418/149, 417/477 [51] Int. Cl Flc /00, F04c 5/00, FOlc 19/00 [50] Field of Search 418/45, 154; 417/474-477; 103/131, 126 S, 149; 230/146, 168; 91/56, 57; 123/8 PA, 8 SS [56] References Cited UNITED STATES PATENTS 2,519,642 8/1950 Ford 103/149 2,849,962 9/1958 Musser 103/149 3,053,236 9/1962 Selfet a1. l23/8SS 3,113,524 12/1963 Fulton 'l03/l 26S 3,152,553 /1964 Rydberg... 103/149 3,176,622 4/1965 Pfeiffer 103/149 3,408,946 1 H1968 McMillan 103/149 FOREIGN PATENTS 554,414 2/1957 Belgium 277/79 657,429 3/1938 Germany 417/477 702,105 l/l954 Great Britain 415/175 Primary Examiner-Carlton R. Croyle Assistant Examiner.lohn .I. Vrablik Attorney-Werner W. Kleeman ing the sleeve outwardly in at least two locations, the rotor effecting the outward deflection of the sleeve as the rotor rotates against the inside wall of the housing to thereby produce a plurality of sealing contacts which divide the space between the housing and the sleeve into traveling pockets. The sealing strips provided at the edges of the sleeve are clamped into portions of the housing and furthermore are acted upon, via a connecting channel, with a pressure medium so as to avoid sealing losses even at high pump speeds and high delivery quantities.

PATENTEDJUN 812m 8588888 SHEET 1 OF 2 INVENTOR 517:5 GF/iIfD S-I'HUBER ATTORNEY PATENTEDJUN 8l97l 8588;888

SHEET 2 OF 2 INVENTOR BY k mm,

ATTORNEY BACKGROUND OF THE INVENTION The instant invention generally relates to pumps and particularly concerns a rotary displacement pump of the type having a multiportion housing with a sleeve disposed in the interior of the housing, the sleeve being formed of an elastic material and displaying sealing strips at the edges thereof and a crosspiece between the suction and delivery sides of the pump, the sleeve being secured against rotation and connected with the housing. In such a pump, a rotor is disposed in the interior of the sleeve for deflecting the same outwardly in at least two locations, the rotor pressing the sleeve at these locations against the inside wall of the housing, the locations effectively performing a traveling motion as the rotor rotates to thus produce sealing locations to divide the cavity or chamber disposed between the housing and the sleeve into traveling delivery pockets. 7

Various embodiments ofdisplacement pumps of the general type above described, are known in the art. Yet, such pumps possess a major drawback in that these pumps can be employed only for low pressures of maximally 3 ATii. (atmospheres absolute pressure) and with a relatively low rotational speed of less than 2,000 rpm. Higher pumps outputs with displacement pumps of the prior art are not possible due to the difficulties attending the sealing off of the edges of the sleeve. In fact, particularly, in the presence of higher pressures, the delivery medium will flow back from the delivery chamber into the suction chamber along the lateral sealing slots of the rotating delivery pockets. The sealing action at the edge of the sleeve cannot be improved by clamping the sleeve edges or flanges more forcefully as the elastic sleeve material oftentimes will be squeezed out of the clamping slot. Moreover, it is a frequent occurrence to have the sleeve in pumps of this type actually disengage itself out of its lateral support.

7 SUMMARY OF THE INVENTION Thus, a need exists for a rotary displacement pump which eliminates the aforementioned drawbacks associated with prior art constructions. It is the primary object of the instant invention to provide a pump which meets this need. Further, more specific, yet equally important objects of the instant invention are:

the provision of a rotary displacement pump which can be operated at considerably high rotational speeds than is the case with prior art constructions;

the provision of a rotary displacement pump in which the delivery quantity of the fluid medium is proportionate to the rotational velocity of the pump by avoiding sealing losses;

the provision of a rotary displacement pump in which the sleeve is laterally held in a simple yet reliable manner and furthermore is hermetically sealed.

These objects as well as other objects which will become apparent as the description proceeds are implemented by the instant invention which comprises a rotary displacement pump of the type generally above described. The rotary displacement pump will be seen to comprise a multiportion housing having a sleeve of elastic material disposed within the interior of the housing, the sleeve being connected with the housing rigidly against rotation and furthermore displaying sealing strips at the edges thereof as well as a crosspiece between the suction and delivery sides of the pump. A rotor is disposed in the interior of the sleeve for deflecting the same outwardly in at least two locations, the rotor pressing the sleeve at the outwardly deflecting locations against the inside wall of the housing, these locations traveling as the rotor rotates to thereby produce sealing contacts dividing the space between tee housing and the sleeve into traveling pockets. Importantly, the instant invention is furthermore characterized by the feature that sealing strips are secured to the edges of the sleeve and are clamped-into portions of the housing, these sealing strips being acted upon by a pressure medium via a connecting channel in a fashion such that sealing losses are avoided.

BRIEF DESCRIPTION OF TEE DRAWINGS The invention itself will be better understood and further advantageous features thereof will become evident from the following detailed description of preferred inventive embodiments, such description referring to the appended sheets of drawings, wherein:

FIG. 1 is a schematic, cross-sectional view of the rotary dis placement pump in accordance with the instant invention;

FIG. 2 is an enlarged view ofa partial section of the pump in accordance with FIG. 1;

FIG. 3 is an illustration taken along line III-III of FIG. 2 depicting an additional embodiment of the rotor in cross section;

FIG. 4 is a schematic view, partially in section, depicting a further embodiment of the rotor in accordance wit the instant invention; and

FIGS. 5ak are each partial sectional views taken through the pump housing depicting various sleeve embodiments in accordance with the instant invention.

DETAILED DESCRIPTION OF PREFERRED INVENTIVE EMBODIMENTS Referring now to FIG. 1, a rotary displacement pump is schematically depicted. A housing 1 structured as a ring having a cylindrical bore 2 is provided for the pump and a sleeve 3 is inserted therein, the sleeve consisting of elastic material and being provided with a crosspiece or web 4 supported in the housing 1. An inlet opening 5 and an outlet opening 6 for the pump are disposed on both sides of the crosspiece 4. The sleeve 3 is ring-shaped and, in its interior, contains a rotor 7 having a shape which deviates from the shape of a circle. In the example of FIG. 1, the rotor shape is that of an ellipse. Rotor 7 serves to press the sleeve 3 against the bore 2 of the housing 1 at two locations diametrically disposed opposite one another such that two sealing contacts 8 and 9 are formed at these locations. The pockets then resulting between the sealing contacts serve to convey the delivery medium such as a gas, a liquid or a pulpy substance between the inlet and outlet openings.

Rotor 7 itself consists of a rotor body 12 spaced from an elastically deformable exterior ring 13 by means of a plurality of balls or rollers as will be discussed in more detail hereinbelow. When the rotor body 12 actually rotates, the sealing Iocations 8 and 9 effectively travel along the circumference of bore 2 of the housing 1 curing the course of which tee stationary exterior ring 13 would successively and elastically deform. Thus, the delivery pockets 10 will travel from the inlet 5 to the outlet 6 of the pump and thus serve to pump the medium contained within tee pockets.

Referring now to FIGS. 2 and 3, the embodiment of the novel rotary pump of the instant invention is depicted in more detail. As is illustrated, a number of rollers or balls 18 are provided in a fashion such that they are distributed at the circumference of what is here shown as a circular shaft 16. An exterior ring 17 is deformed or deflected by the rollers 18 and thus deviates from the exact shape of a circle. The rollers or balls 18 are retained in their respective positions by a cage 19 as best seen in FIG. 3 and thus serve to press the flexible ring 17 as well as sleeve 20 at the respective locations against the wall of e housing. The size and the number of the delivery pockets which, in each instance, are formed between two rollers or roll bodies, is dependent upon the number of roll bodies disposed between flexible ring 17 and the shaft 16. For example, if a conventional roller having a particularly thin exterior ring is used as a rotor, then the distance between two roll bodies of the roller bearing and the delivery pockets formed would be very small by virtue of the larger number of roll bodies provided. In this instance, it is therefore advantageous to provide shaft 16 with a shape having a slightly elliptical cross section, for example, over which the roller bearing is drawn. In this fashion, the construction will also elliptically deform or deflect the exterior ring such that it presses the sleeve, as depicted in FIG. 1, at two locations 8 and 9 against the wall of the housing. However, it should be appreciated that the exterior ring of the roller bearing can itself provide the function of the sleeve.

Housing 1 is a multiportion housing and can be seen to consist of a ring-shaped exterior portion 25 as well as two side flanges 24 with a cylindrical member 23 as best illustrated in FIG. 3. Housing parts 23, 24 and 25 form a hollow cavity 22 which is closed on all sides and in which are held the edges of the sleeve 20 which, on the outside thereof, has sealing strips 50 secured thereto. The sealing strips 50 are constructed as sealing lips which are acted upon by a pressure medium via channel 51 which, for example, is connected with the delivery side 6 of the pump. In this manner, a uniform pressing at any desired strength of the sealing strips to the edges of the sleeve in the housing is achieved such that even with the highest pump pressures, a reliable sealing of the delivery or delivery side of the pump chamber against the suction chamber or suction side thereof and also a reliable and secure clamping of the sleeve are ensured.

A sealing member 52 is provided for sealing against the outside, sealing member 52 being constructed, for example, in the nature of an O-ring selectively supported in housing member 24 or 25. The sealing member 52 serves to seal off the slot between the members 24 and 25.

As shown by a dotted line and referenced by numeral 53, channel 51 can also be outwardly directed, if desired, and connected to an external pressure source 54 which need not be described in more detail for purposes of the invention. In this manner, the sealing strips can be acted upon by a pressure which is independent of the delivery pressure of the pump or by a pressure which is controlled by control means 55 via conduit 56 in dependency upon the pressure on the delivery side 6 of the pump. Accordingly, it is possible to have the sealing strips 50 of the-sleeve 20 acted upon either by a lower, an equal or a higher pressure than that existing on the delivery side of the pump and/or acted upon either by a variable or by a constant pressure.

The sleeve 20 having sealing strips 52 secured to the same is contemplated to be pretensioned on all sides thereof. When in a relaxed condition, the sleeve has a diameter which is small than the external diameter of the cylindrical portion 23 such that the sleeve 20 must also be widened at its edges for mounting within the pump. Furthermore, the length of the cylindrical sleeve can be somewhat smaller such that the sleeve 20 must be stretched for the purpose of inserting the sealing strips 50 thereof into the hollow cavity 22. This pretensioning action is of substantial importance when one is utilizing a rubber/elastic sleeve material to ensure good functioning of the pump in that the pretensioning ensures that the portions of the sleeve which are pressed against the bore of the housing as the rotor rotates will lift themselves again from the bore so as to form the suction chamber. For example, if the sleeve is formed by means of a steel bushing, then the greater restoring force makes the axial pretensioning thereof no longer necessary.

The suction and delivery sides of the pump are separated by a crosspiece or web 26 which comprises an extension of the sleeve 20. Crosspiece 26 is disposed in a groove 57 recessed in housing portion 25. Crosspiece 26 is likewise structured as a lip sealing means within groove 57 and can be acted upon by a pressure medium in exactly the same manner as was the case with sealing strips 50, with the pressure either occurring on the delivery side of the pump or being supplied by an external source, depending upon the particular need.

It is also possible to allow the pressure to act upon sealing strips 50 via crosspiece 26 whose sealing lips are constructed such that one of the lips is pushed away in each instance by the pressure acting on one side, whereas the other lip functions as a seal. In this manner, the pressure of the fluid medium reaches into the groove 57 or between the sealing lips of the crosspiece 26, respectively, from where the fluid medium can be further fed along by means of a connection to the sealing lips 50.

Referring now to FIG. 4, a further embodiment of the rotor is depicted, the rotor comprising two discs 31, 32 disposed on a shaft, the discs being connected by bolts 35, 36 on which two ball bearings 33, 34 are rotatably mounted. Ball bearings 33, 34 serve to push with their exterior rings against the sleeve and, in this manner, effectively produce two sealing locations. However, it is also possible to provide for more than two ball bearings which, of course, would result in a corresponding in crease of the sealing locations.

In FIG. 5, various embodiments of the sleeve and its assembly into the pump is depicted. In all these embodiments, the support on all sides of the sleeve edge having the sealing strips is ensured, such uniform support being necessary for a good functioning of the pump. The only variant features of these embodiments concern the arrangement of the sealing strip, its shape as well as tee material of the sleeve.

Specifically, FIG. 5a corresponds to the embodiment of the sleeve as depicted in FIG. 2 with the exception that the housing portion 25' embraces the sealing strips 50 on the external side as well. In this fashion, it is possible to forgo the O-ring 52 without sacrificing, by such deletion, the sealing action. In FIG. 5a, the channel 51 for acting upon the sealing strip 50 is also illustrated. In the arrangement of FIGS. 5bk, this channel has been deleted for illustrative simplicity. The individual embodiments need no further comment with the exception of the embodiments in FIGS. 50, d, g, k, in which the sleeve and the sealing strips are made of different materials and are connected to one another in a suitable fashion such as vulcanization, for example. In these embodiments, as mentioned, the sleeve can contain various inserts, for example, inserts made of fabric, steel cables, sheet metal, and other flexible and elastic materials.

The rotary displacement pump in accordance with the instant invention substantially enlarges the field of application of such pumps. Whereas, heretofore in the prior art, the maximum work pressure was limited to about 3 Atii. and the rotational velocity to a maximum of 2,000 rpm. by virtue of the described structure of the novel housing and sleeve of the instant invention, it is now possible to obtain with pumps of this type a delivery pressure of at least 5 Atii. and a rotational velocity up to 10,000 r.p.m., a significant achievement when compared with the outputs heretofore obtained.

As should now be apparent, the objects initially set forth at the outset of the specification have been successfully achieved.

What I claim is:

l. A rotary displacement pump having suction and delivery sides, said pump comprising a multiportion housing, a sleeve of elastic material disposed in the interior of said housing and connected with said housing in a rotation-rigid fashion, said sleeve including sealing strips at the edges thereof for sealing and delivery side and suction side from one another and a crosspiece between said suction and delivery sides, a rotor means disposed in the interior of said sleeve for deflecting said sleeve outwardly in at least two locations, said rotor means pressing said sleeve against the inside wall of the housing at said locations which travel as said rotor rotates thereby producing sealing contacts which divide the space between said housing and said sleeve into travelling pockets, and wherein said sealing strips at said edges of said sleeve are clamped into portions of said multiportion housing, and means including a connecting channel for directing a pressure medium to said sealing strips, said pressure medium acting upon said sealing strips to improve the seal thereof between said delivery side and said suction side and to improve clamping of said sleeve in desired position.

2. A rotary displacement pump as defined in claim 1, wherein said crosspiece of said sleeve as well as said sealing strips are clamped into portions of said multiportion housing, both said crosspiece and said sealing strips being acted upon by said pressure medium.

3. A rotary displacement pump as defined in claim 2, wherein said sleeve, said sealing strips thereof and said crosspiece define a unitary, integral structure.

4. A rotary displacement pump as defined in claim 1,

wherein said sleeve when in a relaxed condition, is smaller in 5 both the axial and radial directions than its surrounding housing assembly, such that said sleeve is subjected to axial and tangential tensile stress when said sleeve is mounted in said housing.

5. A rotary displacement pump as defined in claim 1, wherein said sleeve forms an exterior ring of said rotor means.

6. A rotary displacement pump as defined in claim 1,

wherein said rotor means comprises a roller bearing having a thin exterior ring, said roller bearing being secured upon a noncircular shaft.

7. A rotary displacement pump as defined in claim 1, wherein said sealing strips are acted upon by said pressure medium in dependency upon the delivery pressure of said pump.

8. A rotary displacement pump as defined in claim 1,

wherein said sealing strip is acted upon by an external pressure source. 

1. A rotary displacement pump having suction and delivery sides, said pump comprising a multiportion housing, a sleeve of elastic material disposed in the interior of said housing and connected with said housing in a rotation-rigid fashion, said sleeve including sealing strips at the edges thereof for sealing and delivery side and suction side from one another and a crosspiece between said suction and delivery sides, a rotor means disposed in the interior of said sleeve for deflecting said sleeve outwardly in at least two locations, said rotor means pressing said sleeve against the inside wall of the housing at said locations which travel as said rotor rotates thereby producing sealing contacts which divide the space between said housing and said sleeve into travelling pockets, and wherein said sealing strips at said edges of said sleeve are clamped into portions of said multiportion housing, and means including a connecting channel for directing a pressure medium to said sealing strips, said pressure medium acting upon said sealing strips to improve the seal thereof between said delivery side and said suction side and to improve clamping of said sleeve in desired position.
 2. A rotary displacement pump as defined in claim 1, wherein said crosspiece of said sleeve as well as said sealing strips are clamped into portions of said multiportion housing, both said crosspiece and said sealing strips being acted upon by said pressure medium.
 3. A rotary displacement pump as defined in claim 2, wherein said sleeve, said sealing strips thereof and said crosspiece define a unitary, integral structure.
 4. A rotary displacement pump as defined in claim 1, wherein said sleeve when in a relaxed condition, is smaller in both the axial and radial directions than its surrounding housing assembly, such that said sleeve is subjected to axial and tangential tensile stress when said sleeve is mounted in said housing.
 5. A rotary displacement pump as defined in claim 1, wherein said sleeve forms an exterior ring of said rotor means.
 6. A rotary displacement pump as defined in claim 1, wherein said rotor means comprises a roller bearing having a thin exterior ring, said roller bearing being secured upon a noncircular shaft.
 7. A rotary displacement pump as defined in claim 1, wherein said sealing strips are acted upon by said pressure medium in dependency upon the delivery pressure of said pump.
 8. A rotary displacement pump as defined in claim 1, wherein said sealing strip is acted upon by an external pressure source. 